1. Field of the Invention
This invention relates to a seal skirt at the bottom of a slide-glide door panel of the type used in transit vehicles and the mechanism for raising and lowering the skirt as the door panel rotates from open to closed positions and from closed to open positions.
2. Description of Related Art
Slide-glide doors are well known in the art of transit vehicles, for example, buses. Normally, at least one door panel is arranged to cover a portion of the door opening. The door panel has top and bottom pivotal attachments to operating arms extending from a door post positioned at the edge of the door opening. The door posts are driven by a prime mover causing the arms to rotate inwardly away from the opening. The trailing edge of the door panels (when the door is being opened) is pulled into the vehicle guided by a track and the leading edge rotates outward so that when the operating arms have rotated approximately perpendicular to the opening, the door has moved perpendicular to the opening and generally inwardly of the opening. In some transit vehicles, the vehicle floor slopes downwardly to the bottom edge of the door panel. In this case, an accommodation must be made as the door is opened inwardly. This may take the form of a skirt seal movable relative to the bottom of the door. See, for example, U.S. Pat. No. 6,125,768 entitled “Door System for Transit Vehicle” and U.S. Pat. No. 7,143,546 entitled “Sealing Arrangement for a Transit Vehicle.”
The above-referenced patent accommodates the sloped floor without bending or deformation of the door panel. It does so through the use of a helical cam which interfaces with the lower operating arm. Upon rotary motion of the lower door arm relative to the door panel, the helical cam slides a sealing skirt up or down in a path generally parallel to the face of the door panel. To be visually pleasing, this arrangement requires the use of covers on both the inside and the outside of the door. The disclosure of U.S. Pat. No. 7,143,546 is incorporated herein by reference for showing the general arrangement of slide-glide doors in transit vehicles and the operation of such doors when the panels move from the closed to open positions.
Canadian Patent No. 2235456 entitled “Swinging Door Leaf for Vehicles” discloses a swinging door with a sealing strip attached to the lower edge wherein the sealing strip is made entirely of a rubber-elastic material or a synthetic material. The sealing strip has a weak point in the thickness of the sealing strip wherein the sealing strip is rotated about the weak point. Rotation of the door to the open position causes the sealing strip to be raised from the floor by positive mechanical action, however, the return to the sealing position when the door closes entirely relies on the sealing strip falling into place. Moreover, a pocket formed to receive the sealing strip is exposed when the door is opened and is not positively sealed when the door is closed. The accumulation of dust in the pocket could degrade operation.